Maximal vasodilator capacity of resistance vessels has been shown to be reduced in normotensive young men with a family history of hypertension. The present study attempted to examine whether venous distensibility is decreased in normotensive men with hypertensive relatives. The venous pressure-volume relationship was determined in the forearm with a water-filled plethysmograph in 17 normotensive young men with hypertensive relatives (mean blood pressure, 85 ± 2 [SE] mm Hg; age, 22 ± 1 years) and 18 young men with no family history of hypertension (mean blood pressure, 81 ± 2 mm Hg; age, 22 ± 1 years). The venous pressure-volume curve in men with hypertensive relatives as compared to that in men with no famUy history of hypertension was shined toward the pressure axis (p< 0.001). This finding suggests that venous distensibility is decreased in normotensive young men with hypertensive relatives. Administration of phentolamine, 1 mg/min i.v. for 5 minutes, did not alter venous distensibility, and venous distensibility after phentolamine administration was less in men with hypertensive relatives than in men with no family history (p< 0.001), which suggests that decreased venous distensibility found in normotensive young men with hypertensive relatives was unlikely to be related to α-adrenergic mechanisms. These results suggest that aormotensive young men with a family history of hypertension have vascular abnormalities that involve veins as well as arteries.